Torque measuring wrench



Oct 28, 1941. H. Iw. zIMMERMAN 2,260,358

TORQUE MEASURING WRENCH Original Filed March 6, 1937 Patented Oct. 28, 194.1.v

original application 'nieren s, 1937, serial No. f

129,357. Divided and thlspplication February z3, 1939, serial No. 251,848

5Claims.

My inventionlrelates to wrenches, and has to do particularly with -wrenches .adapted `for measuring the force or torque applied therethrough in tightening, loosening or otherwise moving nuts, bolts,'studs and other devices. as Y set forth in my copending application Serial No.

129,357, led March 6, 1937, issued as Letters is a division. i

As is wellknown, the' application of excessive pressure to nuts; bolts, studs. etc., in tightening the same wil1ten`d to break or twist ofi, or other- `wise distort,A the bolt or stud. The 'amount of force or pressure that nay be applied4 through a wrench in such cases is determined, in part,

by the tensile strength of vthe bolt or stud ma.- terial and also somewhat by the depth and pitch of the threads thereof. Itis, therefore, desirable that some means be provided for indicating the amount of force or torque applied through of this is the cylinder head'of an automotive engine, in which case it has been -found that the lack of uniformity in tightening the cylinder head studs results in distortion of the head, which lowersvthe emciency of the engine.

Still further, vit has been found expedient, in.

many cases' where parts are rotatably itted together, to determine the nature of the t between Patent No. 2,151,953, of which this application `reference to the drawing whereinvarious rotatably mounted/devices, such, for example, as crank shafts, lathe spindles. piston and connecting rod mountings, and the like.

A further @meer is m provide a. torque measuring device of the foregoing character which Vis Yquite simple in .construction and embodiesE but very few parts that may be readily and easily assembled and disassembled, is so inexpensive that it ,may readily find its way into automotive and other service stations and work shops of practically all classes, -is substantially foolproof, in operation, and lis adapted to serve lthe intended purpqse in a highly efficient manner ,at all times.

Further objects land advantages willA become .apparent as this description progresses, and by Figure 1 is a top plan view o! one form of wrench embodying my invention;

Fig; 2 is an enlarged, vertical sectional view of the structure shown in Fig. 1; and Y Fig. 3 is a partial side elevational vView of a .torque measuring wrench of the character shown body l0 having oppositely extending arms il,

' each of which is provided with a threaded openthe parts by measuring thev initial force or torque required to relatively rotate such parts.

One example of this is the tting of a bearing,

such as a crank shaft bearing. Another example is the fitting of a piston pin, wherein it is desirable to t the parts in such aA way .thatl the resistance to relative movement does not exceed a predetermined extent. i An additional example is the tting of a lathe spindle to its supporting bearings. f

One of the objects of my invention is-'to provide an improved wrench device that serves Vthe foregoing purposes and by which'gnuts, bolts, studs and the like may be readily tightened to a predetermined extent and any number of. them may be set up successively in a uniform manner.

Another object is to provide a torque measuring `device which is capable, through the`pro vision of suitable adapterdevices, for the measlurlng of the'force or torque required to move"l The lower side of the bodyis provided a continuous, depending annular'4 flange `2li ing l2 adapted to receive the threaded end oi a 'handle member i3. The central portion of the V` body lli is provided with an open top, annular chamber Il, vthe upper portion of which is covered by a 'circular dial member l5 which, in turn, is covered Aby a transparent, circular cover i6. The peripheral edge of the dial member i5 is seated upona shoulder Ily at the upper end of the chamber M and the peripheral edge of the cover I6 is received in an annular groove I8 above the shoulder l'l, theV cover being confined therein by a snap ring IS'ot any suitable and well-known form. The chamber M receives gage-operating mechanism which' willy be d scribed in detail hereinafter.

With

which isexteriorly threaded `to receive a re-` taining ring 2| that rotatably supports andren-1 nects a cup-shaped, shell-'like member 22 to the body m.y 'ro this end, the lower ena-of the ring p 2l is provided with an inwardly extending flange V2|, and the upper end of the cup-shaped member 22 is provided Awith an outwardly extending Iiang'e22', which flanges abut each other as shown in Fig. 2, thereby preventing axial separation of the member 22 from y2l and .ing 2-I and flange 20) body I while-permitting relative rotation between these parts. The member 22,- ring 2| and flange 2i), `when assembled, constitute, in effect, a pairof relatively rotatable shell members rotatable together and relatively about a common axis, which members dei-lne a space 23 in which is received a torsion spring 24. The upper end 24B of the torsion spring is turned lengthwise of the spring to engage an opening 25 formed in the adjacent Wall of the Wrench body I0; and the lower end 24b of the torsion spring is turned likewise to engage an opening 26 in the end wall of ,the member 22. It will, therefore, be clear that, with this arrangement relative rotation'be,

tween the member 22 and the body I0 (including is yieldably opposed by the spring 24.

The lower end of the member 22 non-rotatably receives the upper end of a shank 21 carrying an adapter device 28 which may take the form of asocket' member or other suitable means for engaging the work. The member 22 is further provided internally with an integral, axial, shaftlike extension 29 which projects toward the. bout7 I0 and is rotatably received in an opening 30 in the lower side of the wrench body, which extension serves as a guide bearing, so to speak, for rotation of the member 22.v

the gage dial by movement of the hand 39 in terms of inch-pounds pressure.

In the operation of the gage structure, relative rotation between the member 22 and the body I0 Ycauses relative rotation of the shaft-like extension and gear 32 relative to the gear 33, thereby rotating the gears 33 and 35 and, in turn, the gear 36 and the gage hand 39. It will be appreciated that the relative rotation .of the wrench parts may be of slightlextent and, to facilitate `accurate determination of the force or torque The gage operating mechanism is directly con- A nected to the shaft-like vextension 29. More particularly, the body-engaged end of the shaft 29 is provided with an openingswbich flxedly receives the hub 3| of a comparatively large gear 32, which, in turn, meshes with a smaller gear 33 carriedby a shaft 34 rotatably supported by the body i9 at the bottom'of the chamber i4. The

shaft 34 further supports, abovethegear 33, an. other and larger gear 35 which. in turn. meshes vwith a smaller gear 36 carried by Va shaft 31 which is rotatably supported by and axially of the gear 32. The shaft 31 projects toward the dialfl5, where it is frictionally received in an opening provided in the inner end of a gage hand carrying member 38 which projects outwardly through the dial i5 and the cover I6. The member 38 flxedly supports a gage hand 39, and it is movable relative to the dial |5,`which is provided with a scale-49 adapted to register the extent of relative rotation between the member 22 and body Il) and the extent of wind-up of the torsion spring 24, preferably. in terms of inchpounds pressure, each graduation of the scale 40 indicating for example, 100 inch-pounds pressure. In o rder that the gage hand 39 may alwaysl be properly set to register the pressure with re' spect to the zero mark on the scalem. the fit between the member 38 and the shaft .31 is such condition, under such conditions, the relative sizes of the gears 32 and 33 and the gears 35 andv 36 are such that a very slight relative movement of the wrench parts results in a greatly amplified movement of the gage hand 39.

Various forms of handle devices maybe employed when the Wrench isapplied to the work. For example, in Fig. 3 I show a, handle arrangement of such character that the wrench may be held in engagement with the work with one hand and rotated with the other. Specically, the wrench is provided with a handle 50 having a knob 5l upon which the hand of an operator may be placed for holding the wrench engaged with the work. It is also provided with an offset U shaped hand grip portion 52 which may be grasped by the other hand of the operator for rotating the wrenchstructure, the knob 5i being rotatable upon the hand grip portion 52 to permit of this' action, as will be well understood. The remainder of the structure of this wrench maytake the same form as the structure shown in Fig. 2. Inf-'that case, the wrench body 53 is i substantially axial alignment with the gage that when the member 28 is applied to the work and held stationary. thereby. the outer 4end of the member 38 may be grasped and rotated rela@ tive to the'shaft 31 to move the hand 3 9 to the zero position on the scale 48.

The spring 24 is so constructed that a predetermined initial force or torque is required to overcome its' initial tension and permit relative rotation of the member 22 and the body I5. -It

will be obvious that, with the-member 28 applied Vto the work, and the-handle I3 is rotated in clockwise direction (as viewed in Fig. 1), as soon as the work'oifers sumcient resistance to overcome theV initial tension of the spring 24, the member 22 and body i0 will rotate relatively, the extent of this rotation, and also the extent of increased tension of the spring,

being registered on structure so that the operator may readily look down upon and observe the gage structure in the use of the wrench.

It is believed that the operation and advantages of my invention will be readilyunderstood from the foregoing description. The device may be easily and quickly applied to the .work and it may be 'rotated through the handle devices disclosed. .As the wrench is rotated, and as soon as the initial tension of the torsion spring is overcome, the relatively rotatable wrench parts will rotate relatively, and this will cause actuation of the gage mechanism. The gage mechanism and the relatively rotatable parts are so arranged that the extent of relative movement of the wrench parts'as indicated by the gage mech-4 anism accurately determines the extent of pressure applied to the work. v

1. In a, structureof the classdescribed, a pair of' shell members adapted for rotation together and relatively about a common axis, a coupling member rigidly secured to one of said relatively -rotatable members and rotatablyA interlocked with the other of said rotatable members for coupling said rotatable members for relative rotation, spring means between and enclosed by said shell members and connectedat its ends to said members in such a way as to yieldingly oppose relative rotational movement thereof, handle means on one of said members, work-engaging` means on the other otsaid members, and .indione of said members and rotatable relative to' both said members and coaxial therewith for indicating extent of movement of said members, a second part carried by the other of said members, and a motion-transmitting part between said first and second parts.

2. In structure of the class described, a body member, a shell-like member rotatably carried by said body member and defining with said body member a spring chamber, a pair of opposed handles carried by one of said members, means on the other 'of said members for engaging the same with the work, a torsion spring in said chamber fastened at one end direct to said body member and at its other end direct to said shelllike member and yieldably opposing relative rotation of said members, axially disposed, rotary guide means rigidly carried by one of said members and rotatably engaged with the other of said members, an indicator device carried by and rotatable relative to said body member, gear means between said rotary guide means and said indicator device and adapted to apply rotational movement to said indicator in an amplified manner upon relative rotation of said members, the arrangement being such that the force or torque applied to the wrench is applied through said spring, and means associated with said indicator registering the extent of relative rotation of said members in terms of pressure units.

3, In structure of the class described. a body, v member, a shell-like member rotatably carried by said body member and defining with said body member a spring chamber,handle means carried by one of said members, means on the other of said members for engaging the same with the work, a torsion spring in said chamber connected at one end to said body member and at its other end to said shell-like member and yieldably opposing relative rotation of said members, an axial shaft element on said shell-lile member extending toward said body member and rotatably engaged with the latter, and means for indicating the extent of relative movement between said members as opposed by said spring, including a gear` carried by and rotatable with said shaft element, another gear rotatably carried by said body member', an indicator device rotatable relative to said body member, movement amplifying connections between said gears and said indicator device, and a member calibrated in terms of pressure units carried by said body member and with respect to which said indicator device is rotatable.

4. A torque measuring wrench comprising a body member, handle means on said body mem,-

ber, a second member, 'means secured to both ofy said members for rotatably connecting said second member to said body member for rotation therewith and relatively thereto about a common i axis, a torsion vspring concealed Within and coconnected thereto to yieldably oppose relative rotation thereof, means coaxial with said second member for connecting it with the work, means coaxial with said second member and rotatably engaged with said body member for maintaining va fixed coaxial relationship between said members, and indicating means associated with said members and actuated by relative movementthereof for measuring the pressure applied through the wrench to the work.

5. A torque registering wrench having in combination a shaft, a socket-bearing member fixed -to one end of the shaft, an index operatively connected toA and extending laterally of the other end of the shaft, a rotatable handle `member mountedA on the said other end of the shaft in axially spaced relation to the said socket-bearing member and inwardly of the said index, an elastic torque-transmitting helical spring coupling the handle member with the socket-bearing member and encircling the shaft between confronting end portions of the said members .to hold the latter in axially spaced relation, a

laterally extending scale fixedto the handle member in cooperative relation with the said index, and a cylindrical housing fixed at one end to the socket-bearing member and extending outwardly around thespring and the shaft with its free end in abutment with the rotatable handle member to provide a thrust bearing support for the latter.

HERMAN W. ZIMMERMAN. 

